In recent years, images in a printing system accompanied with a dry electrophotographic system have been improved, and it has been utilized in a printing field for the comparatively small number of print copies. As a result, a desired image level is raised to such an extent that we have not conventionally understood it, and rare usage in the past, for example, printing onto a coated paper sheet, printing for high coverage images, printing for extremely high quality images and images exhibiting subtle tone (color tone), printing continuously for a large number of the same images, or the like has been in heavy usage. Thus, generation of failures which have not been mentioned at all is increased.
There appears one problem such as generation of interferential streaks in a halftone image seemingly originated by light exposure pattern and cutting cycle on the support surface of a photoreceptor. This is a problem which has been recurrently produced in recent years via combination of demand of improving evenness of intermediate color, performance improvement of image forming apparatuses and application for coated paper sheets, and as regards this problem, a quick measure is desired (refer to Patent Documents 1-4, for example).
As to those prior arts, cutting conditions are adjusted, and blast processing and anidization after cutting processing are conducted, but since cutting periodicity itself remains in the case of conventional adjustment techniques, image quality to be highly demanded has still been insufficient, and not only there appears risk for the development of image defects caused by digging-in of a medium and generation of pin holes in the case of the blast processing or the anodization, but also productivity in substrate processing becomes low. Thus, further improvement thereof is demanded.
Patent Document 1: Japanese Patent Open to Public Inspection (O.P.I.) Publication No. 2003-302777
Patent Document 2: Japanese Patent No. 3480618
Patent Document 3: Japanese Patent O.P.I. Publication No. 2001-235885
Patent Document 4: Japanese Patent O.P.I. Publication No. 2003-173037